Maximum Motorsports Road and Track Grip Box For Our 2013 Stang

It’s true that there has never been a better Mustang chassis or suspension from the factory than what is on the current S197 Mustang. That being said, there are always those of us looking to improve where the factory left off.

Our 2013 Mustang GT, Project Silver Bullet has a few lofty goals in mind. We’re out to create a 10-second quarter mile capable machine, that has handling to match, all inspired by the performance of the 2013 ROUSH Performance RS3 Mustang. To do this we’ve already installed a ROUSH Phase 2 supercharger system. With the Dynojet rollers spinning to 497.2 hp and 430.6 ft-lbs, it’s time to match the underhood performance with a top notch suspension, to ensure that Silver Bullet can handle through the curves, and blast down the drag strip with confidence.

To get our front and rear suspension going we’re using Maximum Motorsports’ all-new S197 Road and Track Box suspension system, part number RTB-51.

The Maximum Motorsports S197 Road and Track Grip Box includes carefully selected MM springs and matching Koni single adjustable shocks and struts.

The MM Road and Track Box

We did a lot of street testing to ensure acceptable ride quality, followed by track testing to ensure proper handling when pushed to the limit. -Chuck Schwynoch, Maximum Motorsports

The S197 Road and Track Box is the pinnacle of three years of development work by Maximum Motorsports. According to the company’s Chuck Schwynoch, MM spent three years gathering data on the street and the track. “We did a lot of street testing to ensure acceptable ride quality, followed by track testing to ensure proper handling when pushed to the limit,” says Schwynoch.

MM doesn’t just rely on lap times, and seat of the pants input from drivers either. This data is carefully gathered by data acquisition equipment from Motec. With each component tested and designed to work in unison with it’s counterparts, MM’s goal is the ultimate street and the track experience.

Left: Koni single adjustable shocks and struts were chosen for their damping ability and price. Right: The Maximum Motorsports springs are progressive rate, they lower the car 1.8 inches front, 1.9 inches rear.

What’s In The Box

The Road and Track Box includes all of the parts necessary to take any S197 Mustang from ordinary daily driver, to track super star.

The rest of our MM Road and Track Grip Box included a new front sway bar and bushings, new adjustable rear panhard bar, and new adjustable Extreme Duty, rear lower control arms.

Included in the Road and Track Box are:

  • Maximum Motorsports springs
  • Koni single adjustable shocks and struts
  • Maximum Motorsports front sway bar
  • Maximum Motorsports adjustable panhard bar
  • Maximum Motorsports caster/camber plates
  • Maximum Motorsports sway bar mounts
  • Maximum Motorsports Extreme Duty Rear Lower Control Arms

Urethane front lower control arm bushings are an additional option on this kit. However, MM recommends them only for serious track oriented cars. During their testing Schwynoch says that they found the stock Ford bushings offered the best combination of handling and ride compliance. In fact the system was finalized and tested using the stock Ford bushings.

Left to Right: Disassembly begins in the front by removing the lower strut mounting bolts, the brake line from the strut, and then the bolts that hold the stock strut mount. The strut and front spring assembly come out together as one piece.


Adjustable Dampers

The Koni single adjustable shocks and struts were chosen by Maximum Motorsports for their wide range of adjustability and affordable price. These shocks feature a wide range of rebound settings that make them ideal for street going cars where lower spring rates are typically utilized, all the way up to settings that will match a track oriented spring package that features much higher rates. The struts are adjusted from above using this tool supplied by Koni. Turning counter-clockwise firms the shock setting, while rotating clockwise makes it softer.


The springs for the MM Road and Track box were carefully selected after extensive testing on the street and the track by Maximum Motorsports. Schwynoch says that while they are very proud of the entire Road and Track box package, the springs are what really stand out, “The spring rates were chosen for good handling balance while maintaining good level ride quality.“

The springs are a progressive rate design, meaning they get stiffer the further they’re compressed. Due to the progressive design Schwynoch says the rates can actually vary slightly based on how a Mustang is optioned and what equipment has been added to it. A heavier car is going to compress the spring more at ride height resulting in a slightly higher rate.

The front springs have a 320 pounds/inch rate at ride height, which ramps up to 380 pounds/inch at two inches of compression, or about 1.9 inches of wheel travel. These springs will lower the front end of Project Silver Bulltt by 1.8 inches when compared to the stock ride height.

The rear springs have a rate of 260 pounds/inch at ride height, which ramps up to 380 pounds/inch at two inches of compression which is also two inches of wheel travel since the rear uses a live rear axle. These springs lower the rear of the car 1.9 inches.


The Koni single adjustable shocks and struts were chosen only after finalizing the spring rate for the S197 suspension package. Schwynoch explains, “These offer a firm, performance-oriented ride quality, yet they are not harsh on sharp impacts like expansion joints.” They were also chosen because their price, while not inexpensive, it is less than many more exotic, or custom valved shock options.

Left: Our factory strut mounts utilize a rubber bushing which can move and cause deflection under cornering load. Right: The Maximum Motorsports Caster/Camber plates feature spherical bushings that will not deflect under load, but do allow for proper suspension articulation, and the plates allow for a wider range of front end alignment adjustment.

Sway Bar

The sway bar is also another area where MM spent considerable effort choosing the proper balance. All too often sway bars can be arbitrarily chosen and when not properly matched to a suspension system, they may cause more of handling problem than they help.

Our Maximum Motorsports front sway bar is made from cold formed, heat treated, 500rV4 high tensile steel.  The front sway bar is 36mm in diameter, when adjusted to it’s softest setting Schwynoch says it is only slightly stiffer than the OEM bar. If we choose, we can change the position of the sway bar to get more aggressive with it depending on track conditions.

Left: We're installing MM's Caster/Camber plates which require no drilling and take the place of the factory strut mounts. Center Left and Right: Reassembly of the shocks and struts is the exact opposite of the removal. Right: With the front struts and springs in position we moved up top to secure the strut retaining bolt in place.

The stock rear sway bar is retained. Schwynoch says that with the high rear spring rates the stock rear sway bar is capable of maintaining neutral handling balance. Therefore, replacing it with a heavier duty model is not advised.

Panhard Bar

Since 2005, Mustangs have included a panhard bar as part of their OEM rear suspension. While this is a dramatic improvement over previous designs, the non-adjustable factory bar has no place in a hardcore suspension like ours.

The Maximum Motorsports Panahard bar that’s included in the Road and Track Box is made from tubular polished aluminum rather than stamped steel. It also features spherical rod ends with Teflon-lined bushings and aluminum inserts. This panhard bar not only minimizes deflection by eliminating the soft stock rubber bushings, but also provides adjustability, meaning we can set it for the car’s new ride height, something not possible with the stock panhard bar.

Left: The front sway bar is removed. Center Left: The new Maximum Motorsports front sway bar has three positions for adjustment based on the desired handling characteristics verses the stock sway bar's single position, non-adjustable design. Center Right: MM also sent us a new set of front sway bar bushings which we lubed with their supplied lubricant prior to installation. The bushings must be installed on the front sway bar prior to installing into the car. Right: With everything ready to go, installing the front sway bar completes the installation on our front suspension.

Caster/Camber Plates

On an install of this level, and a car with the handling intentions of Silver Bullet, proper alignment is key. Not only does this help maximize tire wear, but it also helps with handling.  To adjust our front suspension to compensate for the car’s new lowered stance, as well as maximize it’s handling, we need to adjust the caster and camber settings to those recommended by Maximum Motorsports.

We’ll be installing Maximum Motorsports Caster/Camber plates for our 2013 Mustang. These plates not only allow for proper alignment adjustment but are a significant improvement over the stock rubber bushing strut mounts. They provide 1.6 degrees of camber adjustment and 0.7 degrees of caster adjustment. They also feature spherical bearings in place of the stock rubber bushings, this also reduces deflection while still allowing for proper suspension articulation.

Top Left: We begin disassmebly of the rear suspension by supporting the rear differential with stands. Top Right: We removed the rear shocks. Bottom Left: We then removed the rear springs. Bottom Right: The rear control lower control arms are removed next.

Rear Lower Control Arms

We’ll also be installing the included Maximum Motorsports Extreme Duty adjustable rear lower control arms. These tubular steel control arms won’t flex like the factory arms. The new control arms have an offset mounting design that will improve the car’s rear suspension geometry and reduce understeer.

The MM panhard bar features spherical rod ends in place of the factory rubber bushings. It is also adjustable so it’s length can be set to match vehicle ride height and suspension settings.

These control arms use spherical rod ends in place of the spongy rubber factory bushings, this ensures there is no deflection due to movement from bushing compliance when the suspension is under heavy loads. The spherical rod ends will however, allow for proper range of suspension movement. Steel pivot bearings inside the bushings properly support the suspension.

Maximum Motorsports has a chart for rating the power handling capability of these control arms. With the 3.73 gears we plan to install in Silver Bullet, the MM control arms can handle up to 1,116 ft-lbs of torque. Since we don’t plan to get anywhere near that kind of power, these control arms are more than adequate for our application.

Not In The Box

We also installed a wheel hop reduction kit for the third link on the rear suspension. This kit comes from ROUSH performance and is part number 421120. This is the same bracket that ROUSH installs on the 2014 RS3, and is designed to reduce wheel hop in low traction or high output vehicle such as ours.

Left: We also installed this anti-wheel-hop bracket from ROUSH performance. This bracket helps reduce the wheel hop that often plagues high powered S197 Mustangs. Center: The rear seat must be removed to gain access to the mounting bolts for this bracket. Right: With the rear seat out of the way, swapping the bracket is a bolt on operation.

The bracket is designed using the same equipment Ford uses to develop their suspension components. Due to their close work in developing parts with Ford, ROUSH designs this and their other suspension components using OEM specifications to ensure a high quality, highly engineered part.


Installing these components requires no fabrication or special tools. We’ve had great success with both Maximum Motorsports and ROUSH parts in the past, as they typically design everything to be a direct bolt in. A lift does make this job a lot easier, but a skilled enthusiast can handle everything on their garage floor with a jack and jack stands.

Left: The key to getting the rear suspension together properly is to match the length of the new adjustable lower control arms from MM, to the length of the stock control arms, using the bolt locations as a reference. This ensures the rear axle is set straight when everything is tightened. Center Left: With the control arm length set we bolted the control arms into position. Center Right: We then installed our shocks to their upper mounts but not the lower mounts yet. Right: We also set the panhard bar length to the same as the stock bar and then bolted it into place. We will check the bar's length with the suspension at ride height.

If there was one part of the installation that stood out, it is that when installing the rear lower control arms. We set the length to the OEM length first. by lining up the two control arms and comparing the mounting points where the bolts pass through the bushings.

Also since we’re replacing the struts and springs, as well as the caster/camber plates, we don’t need a spring compressor to remove the old springs, these can be removed as an assembly with the struts.

Left: We installed the new rear springs from Maximum Motorsports. Right: We then installed the shocks to their mounts on the differential housing, and tightened all our bolts to the appropriate torque.

The Sum of the Parts

With our Road and Track Box a Mustang can be comfortable enough for commuting to work while also capable of cornering at a continuous force of 1.2g on street tires. – Chuck Schwynoch, Maximum Motorsports

All of these parts sound great on your computer screen or paper. What do they all mean though? As Schwynoch tells us, “With our Road and Track Box a Mustang can be comfortable enough for commuting to work while also capable of cornering at a continuous force of 1.2g on the street.”

1.2g of corner carving capability on street tires is incredible, and Schwynoch notes that this was on street tires, not a sticky track slicks. This level of handling capability easily matches some of the most exotic cars sold today. As a result Project Silver Bullet should hug corners incredibly well, but still not beat us up during our daily commute to the office.

We have yet to take the car to an autocross or road course. We can tell you though that on the street the handling difference is impressive. The car feels a great deal more confident through the turns, with stunning turn in, it goes exactly where it’s pointed with ease. Under hard braking, the brake dive is greatly reduced which will be a a great safety and handling asset.

The changes in ride height are an excellent compromise between the low and slammed stance, and still having adequate ground clearance. As with any lowered car we have to be careful entering curbed parking lots and driveways, or going over speed humps. The suspension handles pavements seams, and dips well, without being too jarring, however it is a much firmer ride than stock, even with the Konis set on full soft.

Based on our driving impressions we’re inclined to agree with what Schwynoch told us, “We surpassed our initial goal of creating a Grip Box suitable for an S197 Mustang used for daily driving, yet also delivering confidence-inspiring performance when pushed to the limit on a race track.”

The rear suspension receives the lion share of the parts from the Road and Track Box.


The front gets a face lift with a new sway bar, sway bar bushings, struts, springs, and camber plates.

With cornering capability to match it’s horsepower output, Project Silver Bullet is well on it’s way to meeting our performance goals and expectations. Stay tuned as we continue to take this 2013 Mustang GT to the next level with more exciting parts as we make our way to the eventual payoff at the track and on the street.

Article Sources

About the author

Don Creason

Don Creason is an automotive journalist with passions that lie from everything classic, all the way to modern muscle. Experienced tech writer, and all around car aficionado, Don's love for both cars and writing makes him the perfect addition to the Power Automedia team of experts.
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